Remember when Madonna's cone bra was the vanguard of nonsilicone breast augmentation? Things were so simple. Not anymore.

A few months ago, the boob wars officially entered the new millennium: Lady Gaga appeared on the cover of Rolling Stone with two machine guns affixed to her chest, pushing her antagonistic ideas about modern feminism and sexuality. Katy Perry, meanwhile, showed up on MTV and YouTube shooting streams of whipped cream from her nipples in the "California Gurls" video, pushing her ideas about, um, the benefits of can-based whip over tub-based whip?

There might not be a lot of deep thought involved in Perry's creative process. But there's a giddy charm in her method. While Gaga breathlessly fulfills pop culture's desire for a blank slate onto which we can project our various sociological theories, Perry stays busy making hits, jokes, and fun. She persuaded onetime murder suspect Snoop Dogg to wear a rainbow-colored cupcake suit and play an evil gummy-bear overlord in one of her videos, just because she can. The packaging of her new album, Teenage Dream, features the singer painted into a bed of cotton candy. Her new Sanskrit tattoo translates as "Go with the flow." And finally, where Gaga told Rolling Stone: "I want to be a legend," Perry just wants "to see your peacock-cock-cock, your peacock-cock," according to the effervescent lyrics for her new song, "Peacock." If it wasn't clear from the beginning, it's totally in-your-face obvious now: These two pop tarts want completely different things.

Not to say Perry's yearnings are somehow less vital. Quite the contrary. Gaga's quest has been bound to the concept of celebrity: "Don't ask me how or why/But I'm gonna make it happen this time/My teenage dream tonight/Fame, doin' it for the fame." But Perry is America's 25-year-old teen dream: "I'm-a get your heart racing/In my skintight jeans/Be your teenage dream tonight." And at its best, her album provides the euphoria of adolescence with just a tinge of wistful nostalgia. There's no overarching concept. The tone moves from silly to stupid to sentimental like a high-schooler switching from class to class. There are love songs, party songs, introspective songs, and motivational songs — plus one about an alien abductor who is also her lover and fills her with poison. Additionally, there's no talk of fame, though Perry is circumspect on the subject: "Fame Mountain is the smallest mountain when you get to the top of it," she recently told the New York Times.

More like a Ben-Day-dotted Lichtenstein cartoon girl than a self-reflexive Warhol idol, Perry is all bright colors and first-thought emotions. Surefire hits such as "Teenage Dream" and the '80s-perfect "Hummingbird Heartbeat" are perked-up simulacra of sudden, straight-faced infatuation, while "Peacock" knowingly plays up the zany sexpot role that got Perry this far. "Last Friday Night (T.G.I.F.)" mixes blacked-out threesomes, semiobsolete Internet lingo, a Lisa Simpson-worthy sax solo (!), and a tidy, uptick beat reminiscent of Cadillac-soundtracking French band Phoenix — it marks the album's most ridiculous (and finest) peak.

As on her 2008 breakthrough One of the Boys, Teenage Dream's (theoretically) less frivolous tracks are more worrisome, such as "Who Am I Living For?" — a lame cut that crawls along to warmed-over Timbaland-style synths while its quasireligious lyrical themes hint at her previous life as a Christian artist. One of the record's omnipresent four-four beats attempts to revive would-be ballad "Pearl," but the maudlin lug would be better suited to a Sisterhood of the Traveling Pants credits sequence.

The only hope for Perry's nonwinking guise comes in the form of the rigorous, rising "Firework," essentially a Taylor Swift song stuffed with enough sparkling pop stuff to level Y100. Perry says the song was inspired by Jack Kerouac's On the Road and that it's about how she wants someone to blow her ashes into the sky upon her demise. However, its simplistic back-patting ("Baby, you're a firework!/Come on, let your colors burst!") indicates nothing of the sort. That's not really important, though. What matters is Perry actually cares about these words, even though they'd likely mean little to anyone older than 15. She means it, and her underrated rocker-chic growl gets that across without the slightest distortion.

Though Perry co-wrote every song on Teenage Dream and she's reportedly too boisterous to be bossed around, this pop star is also smart enough to know when she has found the right partners. After working with her on "I Kissed a Girl" and "Hot n Cold," unearthly Top 40 masterminds Dr. Luke and Max Martin are back, and their uncanny calibration of pop, rock, and dance has already given Perry coveted Song of the Summer honors with "California Gurls" and its less seasonal yet more trenchant followup, "Teenage Dream." Though both tracks rip off previous Luke/Martin hits ("TiK ToK" and "Since U Been Gone," respectively), Perry's plugged-in performances make them worthy sequels, and the record is filled out with new collaborators who try to meet halfway between her pop-rock leanings and their own streamlined R&B tendencies. A producer such as Stargate (Ne-Yo, Rihanna) succeeds by basically following Dr. Luke's formula. But Tricky Stewart (The-Dream, Mariah Carey) has serious trouble bringing out the best in Perry, especially on the instantly dated kiss-off, "Circle the Drain," aimed at emo-rap ex Travis McCoy. It totally bypasses the singer's youthful sweet zone and ends up with something that's simply childish.

No matter how inevitable a song like "California Gurls" sounds, there are no guarantees, even at the highest levels of pop stardom (see Christina Aguilera's career-jeopardizing 2010 superbomb, Bionic). For Madonna or even Britney, changing one's look or sound every album cycle was enough. No more. Largely thanks to Gaga, everything has accelerated. Perry knows she can't quite keep up with that pace. So instead, she's cruising in the wake, comfortably alternating between looking like a blue-haired Smurfette, a Bettie Page acolyte, and Zooey Deschanel. But superstardom is more than an infinite clothes rack; it's about being untouchable and universal at once.

"I don't want people to see that I'm a human being," Gaga has said. Katy Perry doesn't have that problem.